Pressurestat



Dec. 26, '1939. E BRO MNG 2,184,773

PRESSURESTAT Filed April 12, 1938 2 Sheets-Shet 1 Fig.1.

W TNESS Patented Dec. 26, 1939 UNITED STATES 1 PRES SURE STAT James E. Browning, San Antonio, Tex, assignor of one-half to Claude V. Birkhead and Werner N. Beckmann, both of San Antonio, Tex., copartners doing business as Birkhead,' Beckmann, Stanard & Vance Application April 12-, 1938, Serial No. 201,636

7 4 Claims. The invention relates to improvements in devices for use in connection with pressure containing systems of various sorts, to perform work of one kind or another when operated by the system-contained pressure. Exemplary applications of the invention are in connection with steam boilers to control the water boiling means, and in connection with liquefied petroleum plants which require heat to volatilize the liquefied petroleum in cold winter months or when an excess amount of gas is to beused. Obviously rise in pressure of the fluid or vapor in the boiler or in the liquefied petroleum tank may be utilized to diminish the amount of heat applied, and vice versa, and the present invention is well adapted to function in this manner, particularly when used to actuate the burner control and ignition means disclosed in my United States patent application Serial No. 188,159, filed February 1, 1938.

The object of the invention is to provide a novel device responsive to pressures only at a predetermined high pressure and a predetermined low pressure, also a device that will operate with a quick action. The fuel supply and ignition meansor other means actuated by the pressurestat will not, therefore, continually fluctuate, but will be operated only at a predetermined high pressure and a predetermined low pressure.

With the foregoing in view, the invention resides in the novel subject matter hereinafter described and claimed, description being accomplished by reference to the accompanying drawings.

Fig. l is a vertical sectional view through the pressurestat, showing the parts thereof in neutral position.

Fig. 2 is a fragmentary view similar to a portion of Fig. 1 but illustrating the relation of parts which occurs when the predetermined high pressure has been reached.

Fig. 3 is a view simfilar to Fig. 2 but showing the relation of parts which occurs when the predetermined low pressure has been reached.

A preferred construction has been illustrated and will be rather specifically described, with the understanding however, that within the scope of the invention as claimed, variations may be made.

A casing 5 is provided, said casing being divided by a partition 6 into two chambers l and B, said partition being provided with openings 9 surrounded by one valve seat II) which faces the chamber 1, and being provided with another opening ll surrounded by a valve seat l2 which faces the chamber 8. The casing 5 is provided with a threaded nipple or the like l3 communicating with the chamber 7 for connection with any pressure-containing system with which the invention is to be used. The nipple i3 is shown threaded into a boss M on a tank l5 which may be considered as a water boiler or as a tank containing liquefied petroleum. For explanatory purposes, it will also be assumed that heating 10 means is provided for the tank contents and that the pressure-actuated member it which is subjected to the pressure in the chamber 8, controls said heating means in one way or another to supply heat when tank-contained pressure 15 diminishes to a predetermined extent and to discontinue or diminish the heat when the tankcontained pressure increases to a predetermined extent.

One valve H! is cooperable with the seat l0 and is provided with a spring I3 for closing and 20 holding it seated, except when such pressure differences exist in the two chambers l and 8, as to open said valve. Another valve i9 is cooperable with the seat l2 and opens in the opposite direction from the valve ii, that is toward the chamber 3 instead of toward the chamber 1.

A spring 20 is provided for closing this valve I9 and holding it closed until sufiicient pressure exists in the chamber 7 to effect valve opening.

For illustrative purposes, the valves ii and i9 30 are shown provided with appropriate stems 2i and 22 respectively, slidably engaged with suit-' able guides 23 and 2d, the former being carried by the partition 6 and the latter by a head 25 secured in an opening 25 of the casing 5, by a 35 screw plug 21. Stem H is provided with a collar 28 against which one end of the spring l8 abuts, the other end of said spring being disposed against the partition 6. The guide 24 is provided with a collar 29 against which one end of the 40 spring 20 abuts, the other end of this spring being disposed against the valve it. Both collars 28 and 29 are preferably adjustable to vary the strength of the springs i8 and 26, and for illustrative purposes, I have shown nuts 30 and lock 45 said rod being connected in any suitable way with the inner end of the bellows. This rod is surrounded by a spring 31, the upper end of which abuts a collar 38 contacting with the lower end of the plug 35, the lower end of said spring being either disposed against the lower end of the bellows or against some suitable abutment (not shown) carried by the rod 36. Obviously, by adjusting the plug 35, the strength of the spring 31 may be varied, and this strength is always greater than the strength of the spring 8, for the inner end of the bellows i6 is adapted to abut the stem 2! of the valve l1 under predetermined low pressure, the spring 31 then overcoming the spring I8 and holding the valve I! open.

Obviously, movement of the bellows it caused by a predetermined low pressure in the chamber 8, will move the rod 36 downwardly whereas movement of said bellows in the other direction, under a predetermined high pressure in said chamber 8, will move said rod in the opposite direction, and these movements of the rod may be utilized to control the tank-heating means, in any suitable way.

As the pressure in the chamber 1 increases to a predetermined high pressure, the valve I9 is forced open as shown in Fig. 2. This allows the pressure from chamber 1 to pass into chamber 8 and causes the bellows it to collapse as shown in Fig. 2, thus causing the rod 38 to travel upwardly to diminish or discontinue the application of heat to the tank, thereby preventing an increase of pressure above the predetermined high pressure desired in said tank. As the liquid or vapor in the tank cools and the pressure in chamber '1 decreases, valve il' opens sufficiently to equalize the pressure in the chambers l and 8. When this pressure becomes equalized, valve ll closes and with the aid of the pressure in chamber 3, exerts suflicient pressure (as determined by springs 37 and [8) to hold bellows l6 and rod 8 in the neutral position shown in Fig. 1, thus avoiding a premature actuation of the heat-controlling means. If, and as long as, the pressure in chamber 8 is less than that in chamber l, valve ll will remain closed, holding rod 36 in neutral position. When a predetermined low pressure is reached in chamber 1, valve H opens, thus causing the existence of a similar pressure in chamber '8. This causes bellows l6 to expand as shown in Fig. '3, moving valve I? from its seat (by the superior strength of spring 31) causing rod3'5 to move in -a direction to continue the application of heat to the tank. As pressure rises in the tank, valve ll will close, whereupon its stem 2i forces against the bellows l6, again holding said bellows in the neutral position of Fig. 1 until the predetermined high pressure is again reached, at which time'all actions are repeated. Attention is invited to the fact that the bellows i6 is entirely free from connection with both valves H and Hi. This insures that the bellows cannot cause valve fluctuation. In fact, the entire structure is such that it will not operate until the predetermined high pressure or the predetermined low pressure is reached, at which time the device will perform its duty with substantially an instantaneous action.

As excellent results may be obtained from the details shown and described, they are preferably followed. However, as above stated, variations may be made within the scope of the invention-as claimed.

I claim:

1. A pressurestat comprising pressure-actuated work-performing means movable in one direction when subjected to relatively high pressure and movable in the other direction when subjected to relatively low pressure, two valves, and a casing structure cooperable with said workperforming means and said valves in forming one chamber to receive the actuating pressure for said work-performing means, said casing structure having provision for so connecting it with a pressure-containing system that both of said valves control communication between the system and the one chamber aforesaid, said casing having one opening cooperating with one of said valves to place this one chamber in communication with the system when said one valve is subjected to a predetermined low pressure in the system, said casing also having another opening cooperating with the other valve to place the same chamber in communication with the systern when said other valve is subjected to a predetermined high pressure in the system, whereby said work-performing means will be operated uponthe existence of predeterminedhigh and low pressures, said chamber being closed against entrance and exit of pressure except by way of said openings, said work-perform'irigmeans being free from connection with said valves.

2. A structure as specified in claim 1'; said work-performing means being so related with said one valve that the movement of said workperforming means in said other direction will open said one valve and hold it open until sufficient pressure is restored in said chamber to free said work-performing means from said valve.

3. A pressurestat comprising a casing divided by a partition into twochambers, said partition having one valve seat facing one of said chambers, a second valve seat facing the other of said chambers, and openings surrounded by said valve seats, means for placing said one of said chambers in communication with a pressurecontaining system, said other of said chambers being closed against entrance and exit of pressure except by way of said openings, a pressureactuated work-performing member subjected to the pressure in saidother chamber, the movement of said work-performing member under reduced pressure being toward said-one seat and vice versa, one spring-closed valve cooperable with said one seat to 'open when subjected to a predetermined. low pressure in said one chamber, said valve being so related with said work-performing member that said movement of said work-performing member under reduced pressure will open said one valve and hold itopen until predetermined pressure has been restored in said other chamber, a second spring-closed valve cooperable with said second seat toopen when subjected to a predetermined high pressure in said one chamber, and a spring for moving said work-performing member in the direction in which said one valve opens, this spring being of greater strength than the spring which closes said one valve, said work-performing member being free from connection with said valves.

4. A pressurestat comprising a casing having means at its inner end for placing it in communication with a pressure-containing system, said casing having a partition between its inner and outer ends dividing it into two chambers, said partition having one valve'seat facing the innermost of said chambers, a second valve seat facing the outermost of said chambers and openings surrounded by said valve seats, said outer chamber being closed against entrance and exit of pressure except by way of said openings, a pressure-actuated Work-performing member passing through the outer end wall of said casing, a Sylphon bellows around the inner end of said work-performing member and fluid-tightly associated with the latter and said outer end wall to prevent escape of pressure from said outermost chamber, a spring associated with said workperforming member and urging the same and said Sylphon bellows inwardly, the movement of said work-performing member at reduced pressure being effected by said spring, one springclosed valve cooperable with said one seat to open performing member and bellows under reduced 5 pressure will open said one valve and hold it open until predetermined pressure has been restored in said inner chamber, and a second spring-closed valve cooperable with said second seat to open toward said outer chamber when m subjected to a predetermined high pressure in said inner chamber, the spring of the first named valve being of less strength than the spring associated with said work-performing member, said valves being free from connection with said work- 15 performing member.

JAMES E. BROWNING. 

